Compressor



sept. 5, '1933. H, T, MCCARTHY 1,925,333

COMPRESSOR Filed Feb. 25, 1932 Patented Sept. 5, 1933 UNITED STATES PATENT oFFlcE 1,925,333 COMPRESSOR Harvey T. McCarthy, Marlboro, Mass. Application February 2s, 1932. serial No. 594,494 9c1aims. (o1. 23o-175) The present invention relates to compressors and especially to compressors-of a simple and compact construction which are arranged to place fluids under a high degree of compressionl with a minimum expenditure of power.l The present invention involves an improvement on the compresser disclosed in the applicants copending applicatioiLvSerial No. 494,148, filed November 7, 1930, and has for its object the provision of a compressor construction in which the parts are permitted to move freely Without binding, thereby avoiding so far as possible any frictional losses in the operation of said compressor. The invention is particularlycharacterized by its reduction vof the number of moving parts of a compressor to a minimum so that nearly all of the energy of the prime mover is expended in useful work. The above and other objects and advantageous features of the invention Will more fully appear from the following detailed description in connection with the accompanying drawing, in Which:-

Fig. 1 is a vertical sectional viewof a compressor embodying the'invention.

Fig. 2 is a section substantially along the line 2-2 of Fig. 1 looking inthe direction of the arrows.

Fig. 3 is a fragmentary vertical section along the line 3-3 of Fig. l. y

Fig. 4 is a fragmentary vertical section along the line 4-4 of Fig. l." v

Fig. 5 is a fragmentary view showing a modification of the piston structure. l

Like reference characters refer to 4like parts in the different gures. v

Referring to the drawing, the compressor illustrated comprises a housing l formed by an annulus 2 to the opposite edges of which are secured the heads 3 and 4, said heads having openings 5 and'V 6 extending centrally therethrough for the support of the rotating drive shaft 7 of the compressor. Each of the heads is provided with a series of cylindrical seats S'arranged symmetrically about the axis of the drive shaft 7,

corresponding'seats 8 in opposite heads 3 and 4 being in alignment for the rotatable support between them of the' combined cylinder and valve units 10, one lunit being supported ineach pair of seats. Each unit 10 comprises a rectangular portion 11 havingl parallel bores 12 and 13 for the reception of the pistons of the compressor, and trunnion portions 14 and 15 projecting from opposite sides of said rectangular portion 11.

Said trunnion portions are rotatably mounted in the aligned seats 8 in opposite heads 3 and 4 of the casing, so that each unit 10 is arranged for pivotal movement about an axis parallel to the central axis of the drive shaft. p

The drive shaft carries an eccentric cylinder or sleeve 16 between the heads 3 and 4 and said 60. sleeve 16 is surrounded by a ring 17 carrying a plurality of pairs of pistons 18 extending therefrom. The pairs of pistons 18 are received in the parallel bores 12 and 13 of the cylinder units 10, Fig. 2, and by reason of the eccentricity of 6.5, the sleeve with respect to the axis of the shaft, the several pistons occupy different positions within the cylinders. As the drive shaft rotates, each pair of pistons will have a reciprocatory movement imparted thereto accompanied to an oscillatory movement of the corresponding cylinder unit. For any angular position of the drive shaft, the several pairs of pistons will each occupy different positions, so that the pistons successively reach their extreme positions in the cylinder bores `8 through an operating cycle which is yrepeated for each revolution of the drive shaft.

Each cylinder and valve unit provides, as above stated, parallel bores of different diameters receiving thel pistons 18, which are also of different diameters', the connections of each pair of pistons tothe ringA 17 being in alignment With the axis of the drive shaft. The trunnion portions 14 and 15 of the cylinder units each provide` a pair of communicating radial ports 22 and 23 which are angularly displaced to cooperate With the inlet and outlet ports 24 and 25 in the seats in the heads. The ports 22 and 23 in trunnions 14 and l5 are in communication with the parallelvbores 12 and 13, respectively, through passages 26 and 27 in said trunnion portions. When each valve and cylinder unit is oscillated by the rotation of the drive shaft, the ports 22 and 23 operate with the stationary ports 24 and 25 disposed on opposite sides of said trunnion to admit and discharge fluid alternately to and from'the cylinders 12 and 13. The ports 24 in each head are connected to an annular cham- 100 ber 28 formed in each head, each chamber having an inlet pipe 30 connected thereto, and the ports 25 leadto an annular chamber 31 in veach head, the latter chambers each being connected to outlet pipes 32. When rotation of the drive 105 shaft '7 causes oscillation of the trunnions accompanied by reciprocatory movement of the piston in said valve and cylinder unit, the fluid pressure medium is drawn from the chambers 28 and delivered to the chambers 31. 110

A portion 33 of the drive shaft 7 between the points of support in the heads 3 and 4 is square in cross-section for reception in an angular slot 34 in the eccentric sleeve 16 and a bolt 35 extending diametrically through said eccentric sleeve 16 is in threaded engagement with the squared portion 33 of said shaft. Thus turning of the bolt 35 is adapted to shift the center of the sleeve 16 relative to the axis of the shaft, thereby varying the throw of theeccentric from a Zero to a maximum value as determined by the length of the slot 34. Obviously, adjustment of the throw of the eccentric directly controls the length of the stroke of the pistons in their respective bores for varying the output of the pump.

Referring to Figs. 1 and 2, one pair lof the pistons 18a are formed integrally with the ring 17 and extend radially therefrom as shown inA Fig. 2, these pistons comprising master pistons which prevent rotation of the ring 17 relative to the housing. The remaining pairs of pistons 18 are mounted for rocking movement in said ring 17 to permit said pistons to accommodate themselves to the various bores in the several valve and cylinder units. To this end, the ring 17 is recessed at 36 and receives the rounded inner ends of the pistons 18, pins 37 extending through the ring 17 and piston ends, parallei to the shaft axis, serving to pivotally connect the pistons to the ring 17 and permitting the desired rocking movement of said pistons. It Will be apparent that this construction permits-each pair of pistons to accommodate themselves to the cylinder bores in the corresponding "g," Valve and cylinder unit to avoid any binding of the pistons in said cylinders.

The construction of the compressor is arranged to permit the entire compressor mechanism to be self-contained, to avoid any leakage and to eliminate the necessity for the use of large quantities of `packing material; particularly in the pumping of oils, the compressor is thus self-lubricating. As best shown in Fig. 1, the drive shaft 7 is journaled in roller bearings 38 in the head 4 and similar bearings 40 in the head 3, said bearings retaining the shaft against axial movement as well as providing for free rotary movement of said shaft. The end of thebore Vin the head 4 which receives said shaft is closed by a cap 41 which seals said bore against leakage of fluid therethrough. An annular packing ring 42 surrounds the end of the shaft 7 which projects through the head 3 and engages packing 43 in said head 3 to prevent leakage of iluid past `this end of the shaft. The outer ends of the trunnion receiving seats 8 in the heads 3 and 4 are closed by caps 44 to prevent leakage of fluid therethrough, and the heads 3 and 4 are Ysecurely held against the opposite faces of the annulus 2 to prevent leakage of uids between said heads and the annulus 2. 1n this manner, the only packing necessary for the entire compressor and the only place for the compressor to leak is past the packing 43 where the shaft 7 projects through the head 3 and this packing may be readily compressed to prevent leakage by adjustment of the packing ring 42. In this manner the entire compressor is made as a self-contained self-lubricating unit.

In Fig. 5, there is shown a modied construction of a piston 45, the purpose of which is to reduce Wear on the piston surface due to side thrust resulting from the pivotal connection between the piston and theY eccentric ring. The piston 45 carries a guide 46 providing arms 47 adapted Yto slidably engage opposite faces of a cylinder unit 10, the arms 47 effectively preventing any uneven side wear on the piston 45.

From the foregoing, it will be apparent that the present invention is directed to a compressor which is arranged to avoid all friction losses so far as possible by pivotal connection of the pistons in the cylinders to the ring surrounding the eccentric, at least one of said pistons being rigidly connected to the ring to act as a master piston and prevent rotation of the ring. It will also be noted that in the pumping of oils, the uid being pumped provides the lubrication for the compressor in the cylinder walls and in the trunnion portions of the cylinder units, and any leakage of the oil past the pistons in the cylinders, or around the trunnion portions, remains within the compressor since there is no escape for said oil.

I claim:

1. A compressor comprising a casing, a series of seats in said casing, a series of cylinders providing trunnion portions rotatably mounted in said seats, said seats and trunnion portions having cooperating inlet and outlet ports, and said trunnions portions having channels therein connecting said ports to the cylinders, a shaft rotatably mounted in said casing and an eccentric sleeve on said shaft, a ring surrounding said sleeve having a master piston rigidly secured thereto and projecting substantially radially therefrom, and a plurality of pistons pivotally secured to said ring and extending outwardly therefrom, said master piston and said other pistons being received in said cylinders.

2. A compressor comprising a pair of spaced housings, each providing a plurality oi cylindrical seats, corresponding seats being in alignment, a plurality of cylinder units providing oppositely disposed trunnion portions rotatable in said seats, with ports in each of said trunnion portions and said seats for controlling the admission and discharge of fluid to and from cylinders provided in said units, a shaft rotatably `mounted in said housings, an eccentric sleeve on said shaft between said housings, and a ring surrounding said sleeve having a master piston rigidly secured thereto and projecting radially therefrom and a plurality'of pistons pivotally secured to said ring and extending outwardly therefrom, said .master piston andsaid other pistons being received in the cylinders in said cylinder units.

3. A compressor comprising a pair of spaced housings, each providing spaced annular chambers arranged on opposite sides of cylindrical seats, corresponding seatsin opposite housings being in alignment, a plurality of cylinder units providing parallel cylinder bores and oppositely disposed trunnion portions rotatable in said seats with cooperating ports in each of said trunnion portions and said seats controlling the admission and discharge of fluid to and from said cylinder bores, each of said units having a pair of channels, and eachf'channel connecting one of said hores to the ports in the adjacent trunnion portion, a .shaft rotatably mountedl in said housing and having an eccentric sleeve thereon, a vring surrounding said sleeve having `a lpair of Aparallel master pistons rigidly secured thereto and projecting substantially radially therefrom, and a plurality of pairs of pistons pivotally secured to said ring and extending outwardly therefrom.

4. A compressor comprising a pair of spaced housings, each providing spaced annular chambers arranged on oppositeV sides of cylindrical seats, corresponding seats in opposite housings being in alignment, a plurality of cylinder units providing parallel cylinder bores and oppositely disposed trunnion portions rotatable in said seats with cooperating ports in each of said trunnion portions and said seats controlling the admission and discharge of fluid to and from said cylinder bores, each of said units having a pair of channels, and each channel connecting one of said bores to the ports in the adjacent trunnion portion, a shaft rotatably mounted in said housing and having an eccentric sleeve thereon, a ring surrounding said sleeve having a pair of parallel master pistons rigidly secured thereto and projecting substantially radially therefrom, and a plurality of pairs of pistons pivotally secured to said ring and extendingvoutvvardly therefrom, said master pistons being received in the parallel bores of one of said cylinder units and the other pistons being received in the parallel bores of the other cylinder units.

5. A compressor comprising a casing having a series of pairs of seats therein, the seats of each pair being in alignment, a series of cylinder units each providing trunnion portions rotatably mounted in said seats, at least one of the trunnion portions of each cylinder unit being provided With ports for cooperation with corresponding ports in the seats in which said trunnion portions are mounted, said trunnion ports being connected by channels to bores provided in said cylinder units with said ports controlling the-admission and discharge of fluid to and from said cylinder bores, a drive shaft rotatably mounted in said casing and having an eccentric sleeve thereon, a ring surrounding said sleeve and having a master piston extending radially therefrom, and a plurality of other pistons pivotally secured to said ring, said master piston and said other pistons being received in bores in said cylinder units.

6. A compressor comprising a casing providing concentric annular chambers, a shaft rotatably mounted inl said casing, a series of angularly spaced trunnion seats symmetrically arranged between said chambers, a series of cylinders providing trunnion portions rotatably mounted in said seats, an eccentric sleeve mounted on said shaft and a ring surrounding said sleeve pro# viding a plurality of radially extending pistons directly connected thereto receivable in said cylinders, whereby rotation of said shaft causes said pistons to reciprocate in said cylinders accompanied by oscillatory movement of said cylinders with each of said cylinders occupying a different angular relation with respect to said shaft.

7. A compressor comprising a pair of spaced housings, each having a cylindrical trunnion seat and each providing separate chambers arranged on opposite sides of said cylindrical seats and a cylinder unit providing parallel bores and oppositely disposed integral trunnion portions rotatable in said cylindrical seats, Withports in each of said trunnion portions and said seats controlling the admission and discharge of fluid to and from said chambers, said unit having a pair of channels, each channel connecting one of said bores to the ports in the adjacent trunnion portion.

8. A compressor comprising a pair of spaced housings, each having a cylindrical trunnion seat and each providing separate chambers arranged on opposite sides of said cylindrical seats and a cylinder unit providing parallel bores of different diameters and oppositely disposed trunnion portionsv rotatable in said seats, with cooperating ports in each of said trunnion portions and said seats controlling the admission and discharge of fluid to and from said chambers and with the pressure and volume of the fluid being different for each cylinder, said unit having a pair of channels, each channel connecting one of said bores to the ports in the adjacent trunnion portion.

9. A compressor comprising a fixed housing, a shaft, a portion of which is rectangular in cross section rotatably mounted in said housing, a cylinder pivotally mounted in said housing on an axis parallel to said shaft axis, an eccentric having a rectangular slot therein carried by the rectangular portion of said shaft, a ring surrounding said eccentric and carrying a piston movable in said cylinder, and an adjusting screw passing through said eccentric land shaft for movement of said eccentric at right angles to said shaft for adjusting the throw of said eccentric with respect to the axis lof said shaft to vary the displacement of said piston in said cylinder.

HARVEY T. MCCARTHY. 1 

